The present invention relates to a method for the manufacture of a printed, pre-creased packing material web provided with opening indications.
In the manufacture of modern consumer packages, in particular milk packages, high-capacity packing machines are used in which a web of plastic-coated packing material is converted to a tube, in that the longitudinal edges of the web are joined to one another and are sealed together. The tube so formed is filled with contents and sealed off in narrow sealing zones situated at a distance from each other transversely to the tube formed. The tube parts, sealed in this manner and filled with contents, may be given e.g. a parallelepipedic shape by fold-forming, which is done appropriately with the help of a crease-line pattern, facilitating the folding, which is impressed beforehand onto the packing material web.
It is necessary that such consumer packages should be provided with an informative text concerning the contents. It is also the wish of the producers that the packages should be provided with a form of advertising text and trade mark, so as to ensure that the producer's product can be distinguished from other products on the market.
Since the packages are identical in their shape and design when they are manufactured in the same type of packing machines, and the volume is standarized, the packing material for their manufacture will be the same for different producers and similarly the crease-line patterns impressed onto the packing material web, the opening arrangements etc. are the same.
In order to keep the price of the packing material low, the material must be produced in a rational manner on high-capacity machines. Thus, the impression of the crease-line patterns, the plastic coating etc. will take place at high speed, and that wide paper or cardboard webs will be used. Because different producers, of e.g. milk products, who use the packages in question demand different decorations and text arrangements on the packing material it is difficult, however, to carry out a rational production of packing material, since a substitution of the printing mechanism often has to be made when the printing of a wide web comprising five or more package widths takes place simultaneously. Moreover, unreasonable large wastage arises in connection with running in and lining up of the printing.
Since the packing material, with the exception of the decoration and text printed onto the material, is the same for all producers and users of the packing system in question, it has been found that it is rational to manufacture the packing material in wide webs and provide these webs with crease-line patterns, opening indications and plastic coatings, as well as possible coverings with metal foil, whereupon the said wide webs are cut up into partial webs. Each partial web comprises a complete crease-line pattern width, which partial webs are rolled up into large magazine rolls which are suitable for transport. In this manner the main manufacture of the packing material can be concentrated onto a small number of production locations with high-capacity machines, while the printing of the decorations of the individual users or producers may take place at a number of smaller processing units, to which the large transport rolls with base material are transported. At these processing locations the printing of the partial webs can take place with the help of relatively simple and possibly relatively slow-running printing presses. The decoration of each producer or user is printed onto a packing material web of suitable width and the intended crease-line pattern and the web is rolled up into magazine rolls of a size adapted to the packing machines.
Through such a process the wastage during running in, among other things, will be considerably reduced.